Episode Synopsis: Pretty Little Liars Season 4 Episode 13 “Grave New World”- In the special Halloween episode of “Pretty Little Liars,” entitled “Grave New World,” airing Tuesday, October 22nd (8:00 – 9:00 PM ET/PT), Aria, Emily, Hanna and Spencer crash the Ravenswood Founders Day Celebration after finding a clue in “A’s” new lair that Ali may indeed be alive. Dressed in their finest Edwardian wear, the ladies hit the creepy cemetery party to find Ali before “A” can. But if Ali is truly alive, could the PLLs be leading “A” straight to their friend without knowing it? With Ezra lurking in the shadows, “A” may be closer than the girls realize.